This invention relates to the remote steering control of outboard motors of different power used for the propulsion of vessels of various size. It is the adaptation of a steering servo to an outboard motor unit that is involved, the outboard motor and its accessories and controls being incorporated in the powerhead from which a drive tube depends into the water where the propeller assembly operates, and all of which is pivotally carried by a mounting bracket secured by a clamp frame to the transom of-the vessel so as to swing upwardly on a transverse axis to avoid grounding, and so as to be trimmed for optimum propulsion.
Basic steering is by means of vertical pivoting of the powerhead-drive tube-propeller assembly on the swinging bracket, with a forwardly projecting steering tiller arm and grip or handle. Power steering is by means of a servo unit, preferably electrical, with a tiller member reacting from the aforesaid mounting bracket. It is a general object of this invention to adapt such a power steering servo unit to outboard powerheads ranging in power, for example from approximately 10 HP to 27 HP, the sizes of the powerheads differing proportionately. Therefore, it is an object to compensate for off-center positioning of the servo unit with respect to the steering axis of the powerhead of whatever size within a range of sizes designed for, and to compensate for deflections that result in misalignment of the mechanical movements involved. That is, the steering center of the steering servo is not likely to be concentric with the steering center of the powerhead. However, a tight and reliable steering relationship is to be desired and is maintained, as will be shown and described.
The basic function of steering is of primary concern, it being an object of this invention to provide a hand held steering station that is extended by cable or wireless to any desired location aboard the vessel being operated thereby. The hand held station and supporting functions involving throttling, shifting, fuel and electrical battery power are state of the art, and therefore are not, shown herein.
Outboard motor powerheads are of compact design with the basic controls hereinabove referred to incorporated in the powerhead for control. The typical powerhead is enhanced by a tight fitting housing, at the immediate exterior of which all of the functional controls are accessible for direct manual operation or by remote control. It is an object of this invention to provide electrical servo steering operation controlled remotely by a mobile hand held pilot station. Electrical power for operation of this servo unit is provided by, the existent battery power supply of the outboard motor.
It is an object of this invention to adapt a steering servo to the powerhead of an outboard motor, for steering the vessel powered thereby from a remote hand held pilot station. Outboard motors of the type under consideration have a steering bracket to carry the tiller arm and with an attachment face for the connection of remote cable steering, and this steering bracket closely overlies the mounting bracket that is carried by the clamp frame. It is this steering bracket and mounting bracket relationship that is advantageously employed herein to adapt the servo unit characterized by the servo motor attached to said face of the steering bracket and by a stationary tiller member anchored to the mounting bracket.
The steering of the vessel is a constant function that requires instant response and rapid operation with substantial torque. It is an object of this invention to provide these requirements by employing a small high speed continuous duty motor with high rate gear reduction to a pinion gear that shifts the tiller member from right to left. In practice, the motor servo has a geared head with a high ratio gear train that is for all intents and purposes non-reversible. That is, the gear train effectively locks the steering position when the servo is deenergized, the small high speed motor being characterized by quick acceleration and quick deceleration as well.
The steering servo unit herein disclosed is characterized by an arcuately shaped geared segment that is shifted left to right by a motor driven pinion gear. The shiftable segment carries a tiller member in alignment with the steering center of the steering servo unit, it being an object of this invention to position said steering center approximately coincidental with the steering center lf the outboard motor powerhead. It is highly improbable that the steering center and turning center will coincide. But, it is a certainty that the steering center of the servo unit will be ahead of or behind the turning center of the powerhead. For example, FIG. 10 of the drawings illustrates a small sized powerhead adaptation with a steering center aft of the turning center; whereas FIG. 11 illustrates a large sized powerhead adaptation with the steering center forward of the turning center. It is to be observed that in either situation the steering center of the servo unit shifts laterally from the center alignment of the powerhead turning center (when turning right or left) as much as 4.degree. to 5.degree.. Accordingly, it is an object of this invention to provide a steering servo to powerhead adapter that compensates for angular displacements of said steering and turning centers, as is caused by the inherent eccentric relationships between these two distinct centers of -steering and turning.